The present invention relates to a dual flush-volume valve assembly for a toilet tank. More particularly, the invention provides a dual flush-volume valve assembly for a toilet tank that offers improved control over the volume of the low-volume flush.
In the past, most toilets manufactured in the U.S. discharged approximately 3-5 gallons of water per flush. More recently, however, concerns with water conservation, combined with federal law requiring new toilets to have a maximum discharge volume of 1.6 gallons per flush, have led to the development of new water-conserving toilet systems and various devices for reducing the water consumption of older toilets.
One example of a device used to increase the efficiency of older toilets is a dual flush-volume toilet tank outflow valve assembly. Dual flush valve assemblies utilize separate flush valves that discharge different amounts of water for flushing solid and liquid waste. In one type of dual flush valve assembly, a high-volume flush valve is positioned near the bottom of the toilet tank to pass a higher volume of water for flushing solid waste, and a low-volume flush valve is positioned higher in the toilet tank for passing a lower volume of water for flushing liquid waste. Thus, a user may select a high-volume flush when clogging presents a problem, and otherwise use a low-volume flush.
While known dual flush-volume valve assemblies do offer improved water conservation relative to older, high-volume toilet systems, they also have several shortcomings. For example, known dual flush-volume valve assemblies permit little, if any, adjustment of the relative volumes of the low-volume flush and the high-volume flush. This can pose a problem in retrofitting older toilet tanks, as the volume of water passed from the toilet tank during a low-volume flush may be dependent upon the shape of the toilet tank. As an example, when using a dual valve assembly of a given height, more water may be discharged by the low-volume valve from a taller tank than from a shorter tank, as the level of water in the shorter tank may be closer to the low-volume valve than in the taller tank. This may cause problems with flushing, as an inadequate amount of water to flush waste from the toilet bowl may be discharged if the maximum water level in the toilet tank is too close to the low-volume valve.
Another problem with known dual flush valve assemblies is that the pipe that supports the low-volume flush valve is generally horizontally offset from the outflow hole in the bottom of the toilet tank. Thus, water that is discharged through the low volume valve must flow at least somewhat horizontally to reach toilet tank outflow hole. This may decrease the velocity of the flush, and thus may also decrease the effectiveness of the flush.
The present invention provides a dual flush-volume outflow valve assembly for a toilet tank. The outflow valve assembly comprises a base having an opening configured to pass water out of the toilet tank, a lower outflow tube section extending upwardly from the base, and an upper outflow tube section slidingly coupled to and extending upwardly from the lower outflow tube section. The lower outflow tube has a hollow interior and includes a high-volume flush valve positioned to pass a first, larger volume of water from the toilet tank to the toilet bowl when opened. The upper outflow tube section has a hollow interior and includes a low-volume flush valve positioned to pass a second, smaller volume of water from the toilet tank to the toilet bowl when opened. In some embodiments, the hollow interiors of the upper outflow tube section and the lower outflow tube section are positioned over and in line with the opening.